Multistereophonic speaker switching device

ABSTRACT

Main left and right speaker positive and negative input circuits connectable to a stereophonic unit amplifier circuit are connected in the device through a series of switches to a series of sets of left and right speaker positive and negative output circuits, each set of left and right speaker positive and negative output circuits being connectable to a set of left and right speakers. Each of the switches is of double pole type so that actuation of one switch simultaneously connects one of the sets of left and right speaker positive and negative output circuits to the main left and right speaker positive and negative input circuits permitting the connection of a given number of left and right speaker sets into the stereophonic amplifier circuit. A low resistance resistor is connected in series into at least one of the positive and negative input circuits of the main left and right speaker input circuits to provide a load for and prevent damage to the transistors of a transistor circuit type of stereophonic unit, and a higher resistance resistor is connected in parallel across each of the main left and right speaker positive and negative input circuits to prevent overloading of vacuum tubes of a vacuum tube type of stereophonic unit, thereby permitting the device to be used with either a transistor circuit type or a vacuum tube type of stereophonic unit.

United States Patent Vorgan 1 May 9, 1972 [54] MULTISTEREOPHONIC SPEAKER SWITCHING DEVICE ABSTRACT [72] Inventor: Harry Vorgan, 3676 Stone Canyon Main left and right speaker positive and negative input circuits Avenue, Sherman Oaks C lif 91403 connectable to a stereophonic unit amplifier circuit are connected in the device through a series of switches to a series of Filed! y 1970 sets of left and right speaker positive and negative output cir- [21] APP] 40,939 cuits, each set of left and right speaker positive and negative output circuits being connectable to a set of left and right speakers. Each of the switches is of double pole type so that [52] US. Cl. ..179/1 SW, 328/8 actuation of one switch simultaneously connects one of the [51] Int. Cl ...H04r 5/00, H01r 13/70 sets of left and right speaker positive and negative output cir- [58] Field of Search ..l79/1 SW, 1 B, l G, 1 A; cuits to the main left and right speaker positive and negative 330/192, 194, 196, 198; 307/92, 202, 98; 328/8 input circuits permitting the connection of a given number of left and right speaker sets into the stereophonic amplifier cir- 5 R fe n Cited cuit. A low resistance resistor is connected in series into at least one of the positive and negative input circuits of the main UNITED STATES PATENTS left and right speaker input circuits to provide a load for and prevent damage to the transistors of a transistor circuit type of 2 stereophonic unit, and a higher resistance resistor is connected in parallel across each of the main left and right 3'142Ol9 7/1964 Favm 330/194 speaker positive and negative input circuits to prevent over- 2808472 10/1957 Meewezen 330/192 loading of vacuum tubes of a vacuum tube type of 3,365,675 1/1968 Gaddy et al ..330/l92 Primary E.mminerKathleen H. Claffy Assistant Examiner-Douglas W. Olms A!l0rney-Mahoney, Hornbaker & Schick stereophonic unit, thereby permitting the device to be used with either a transistor circuit type or a vacuum tube type of stereophonic unit.

7 Claims, 2 Drawing Figures 38 SWI SW2 S 3 SW4 SW5 s a, "7 so, 7 62 7 g4, 7 g a 36 tape ates sa 70 L 72 74 R76 L R -ao; 82 -a4- -86;

AMPLIFIER MULTISTEREOPHONIC SPEAKER SWITCHING DEVICE BACKGROUND OF THE INVENTION This invention relates to a multistereophonic speaker switching device and more particularly, to such a device connectable to either of a vacuum tube circuit type or a transistor circuit type of stereophonic unit amplifier circuit and permitting a series of left and right speakers connected thereto to be selectively switched into said amplifier circuit without damage to either transistors or vacuum tubes of said amplifier circuit. Thus, with the protection provided by the unique switching device, the switching device may be alternately used for connecting speakers into'either a vacuum tube circuit type or a transistor circuit type of stereophonic unit amplifier circuit and without damage to said circuit.

Various prior switching devices have heretofore been pro vided for selectively connecting speaker sets to stereophonic unit amplifier circuits in order to permit the use of multiple speaker sets positioned at various locations in a given room or each set positioned in a different room. In every case to my knowledge, however, all such prior switching devices have been of the single purpose type, that is, if the stereophonic unit amplifier circuit is of the vacuum tube circuit type, a particular form of switching device has been required to be used in order to prevent damage to the vacuum tubes of such amplifier circuit, and if the stereophonic unit amplifier circuit is of the transistor circuit type a distinctly different form of switching device must be used in order to prevent damage to the transistors of such amplifier circuit. This results, obviously, in a special form of switching device, depending on the particular form of stereophonic unit and where mistakes have been made, severe damage can result.

For instance, unless the proper overload protection is provided for the vacuum tubes of a vacuum tube circuit type of stereophonic unit amplifier circuit, such overloading can take place destroying the functioning of the stereophonic unit and various components thereof including the vacuum tubes. On the other hand, a transistor circuit type of stereophonic unit amplifier circuit requires the protection of minimum load in order to prevent damage to such amplifier circuit including the transistors thereof. The two different types of stereophonic unit amplifier circuits have, therefore, completely different protection requirements and no one has heretofore solved the problem of combining the two.

OBJECTS AND SUMMARY OF THE INVENTION It is, therefore, an object of this invention to provide a multistereophonic speaker switching device usable for selectively connecting one or a series of sets of speakers into a stereophonic unit amplifier circuit without regard as to whether the amplifier circuit is of the vacuum tube circuit type or of the transistor circuit type while still protecting such amplifier circuit against damage. According to the principles of the present invention, the switching device includes permanently in the circuitry thereof a relatively high resistance resistor connected in parallel across each of the main left and right speaker positive and negative input circuits serving as overload protection for the vacuum tubes of a vacuum tube type of stereophonic unit in the event such unit is of the vacuum tube type. At the same time, the switching device includes a relatively low resistance resistorconnected in series permanently into at least one of the positive and negative input circuits of said main left and right speaker input circuits to always provide a minimum load and prevent damage to the transistors of a transistor circuit type of stereophonic unit in the event that such stereophonic unit is of the transistor type. Thus, the stereophonic unit is properly protected for either eventuality of construction and the switching device may be used alternately between such types of units without the danger of damage to either.

It is a further object of this invention to provide a multistereophonic speaker switching device having the foregoing alternate vacuum tube and transistor protection circuitry wherein each set of multiple sets of left and right speakers may be selectively connected to the stereophonic unit amplifier circuit by such device and each such set may be so connected by a single switch for maximum convenience in use thereof. Each set of left and right speaker positive and negative output circuits connectable to the speaker sets are provided with a double pull switch so that actuation of one of said switches will simultaneously connect both of the left and right speakers of that particular set to the stereophonic unit amplifier circuit. Thus, the present invention provides a switching device having the foregoing discussed alternate vacuum tube and transistor protection with the additional feature of maximum switching convenience for selectively connecting various sets of the speakers into the stereophonic unit.

It is also an object of this invention to provide a multistereophonic speaker switching device satisfying the foregoing objects in a relatively simple and inexpensive manner so as to be marketable on a competitive basis. The alterations from the prior devices providing the unique switching device of the present invention may be incorporated at a relatively slight expense and with little additional labor cost despite the major advance of the device of the present invention over similar devices heretofore provided.

Other objects and advantages of the invention will be apparent from the following specification and the accompanying drawing which are for the purpose of illustration only.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a front elevational view of an embodiment of the multistereophonic speaker switching device of the present invention and showing the switch buttons for operating the switches thereof; and

FIG. 2 is a circuit diagram of the switching device of FIG. 1 illustrated connected into a typical amplifier circuit of a typical stereophonic unit.

DESCRIPTION OF THE BEST EMBODIMENT CONTEMPLATED Referring to FIG. 2 of the drawing, an embodiment of the multistereophonic speaker switching device of the present invention is shown in circuit diagram form generally indicated at 10, and includes a main left speaker positive input circuit 12, a main left speaker negative input circuit 14, a main right speaker positive input circuit 16 and a main right speaker negative input circuit 18. The main left speaker positive and negative input circuits 12 and 14 are appropriately connected to left positive and negative output circuits 20 and 22 of a typical stereophonic unit amplifier 24, and the main right speaker positive and negative input circuits 16 and 18 are appropriately connected to right positive and negative output circuits 26 and 28 of said amplifier. In view of the unique protection characteristics of the multistereophonic speaker switching device of the present invention, the stereophonic unit amplifier 24 may be of either of vacuum tube circuit type or transistor circuit type as will be hereinafter discussed more in detail.

A relatively large resistance resistor 30, preferably in the order of 50 ohms, is connected in parallel across the main left speaker positive and negative input circuits 12 and 14 within the switching device, and a similar relatively large resistance resistor 32, preferably in the order of 50 ohms, is connected in parallel across the main right speaker positive and negative input circuits l6 and 18. Also within the switching device, a relatively low resistance resistor 34, preferably in the order of l to 4 ohms, is connected in series in one of the main left speaker positive and negative input circuits 12 and 14, preferably the main left speaker positive input circuit 12, and a relatively low resistance resistor 36, preferably in the order of l to 4 ohms, is connected in series in one of the main right speaker positive and negative input circuits 16 and 18, preferably the main right speaker positive input circuit 16. The purpose of the resistors 30 and 32 is to provide protection for vacuum tubes of the stereophonic unit amplifier 24 in the event the amplifier is of the vacuum tube circuit type and the purpose of the resistors 34 and 36 is to provide protection for transistors of the stereophonic unit amplifier 24 in the event the amplifier is of the transistor circuit type, again as will be hereinafter discussed more in detail.

A series of preferably five and preferably double pole, switches 38, 40, 42, 44 and 46 are connected with one pole to the left positive output amplifier circuit and another pole to the right positive output amplifier circuit 26, said one pole of said switches being connected therethrough to a different one of a series of five left speaker positive output circuits 48, 50, 52, 54 and 56, and said other pole of said switches being connected one each to a different one of a series of right speaker positive output circuits 58, 60, 62, 64 and 66. The main left speaker negative input circuit is preferably connected directly to all of a series of left speaker negative output circuits 68, 70, 72, 74 and 76, and the main right speaker negative input circuit is preferably directly connected to all of a series of right speaker negative output circuits 78, 80, 82, 84 and 86, with each pair or set of left speaker positive and negative output circuits and each pair or set of right speaker positive and negative output circuits being separately connectable to an appropriate speaker.

For convenience in manufacture of the switching device of the present invention, the circuit described may be of printed circuit board type having the various resistors and switches connected thereto in usual manner. Furthermore, the entire circuit may be enclosed as a unit in a typical cabinet 88 shown in FIG 1 with the switches 38, 40, 42, 44 and 46 actionable by pushbuttons 90, 92, 94, 96 and 98 respectively. Typical for the switches 38, 40, 42, 44 and 46 would be of the construction wherein they are pushed in to lock and complete the respective circuits to the speakers and are merely again pushed to release and interrupt said circuits.

Thus, according to the principles of the present invention, an embodiment of switching device is shown and described for selectively connecting sets of speakers into the stereophonic unit amplifier 24, but more important, the relatively large resistance resistors 30 and 32 connected in parallel across the main left and right speaker positive and negative input circuits 12, 14, 16 and 18 prevent any overloading of vacuum tubes in said amplifier in the event said amplifier is of the vacuum tube circuit type. At the same time, the relatively low resistance resistors 34 and 36 connected in series in the main left and right speaker positive input circuits l2 and 16 provide a minimum load for transistors of the amplifier 24 preventing any damage to said transistors if the amplifier is of the transistor circuit type. As a result, the switching device of the present invention may be alternately used with stereophonic units of either type and no damage can result to such units, the vacuum tube circuit type operating satisfactorily despite the low resistance resistors 34 and 36 and the transistor circuit type operating satisfactorily despite the relatively large resistance resistors 30 and 32.

lclaim:

1. In a device for switch-connecting single and multiple pairs of left and right stereophonic speakers into a stereophonic unit amplifier circuit wherein the stereophonic unit may be either of a vacuum tube circuit type and a transistor circuit type; the combination of: main left speaker positive and negative input circuits and main right speaker positive and negative input circuits connectable to a stereophonic unit amplifier circuit; sets of left and right speaker positive and negative output circuits, each set of left speaker positive and negative output circuits having a corresponding set of right speaker positive and negative output circuits and each of said sets being connectable to a speaker; switch means selectively operable for selectively directing said main left speaker positive and negative input circuits into each set of left speaker positive and negative output circuits and for selectively directing said main right speaker positive and negative input circuits into each set of right speaker positive and negative output circuits; first resistor means connected in series in at least one of said main left speaker positive and negative input circuits and in at least one of said main right speaker positive and negative input circuits of a resistance for always providing a load for and preventing damage to transistors of a transistor circuit type of stereophonic unit in the event said unit is of the type and regardless of said operation of said switch means; and second resistor means connected in parallel across said main left speaker positive and negative input circuits and across said main right speaker positive and negative input circuits of a resistance for preventing overloading of vacuum tubes of a vacuum tube type of stereophonic unit in the event said unit is of said type and regardless of said operation of said switch means.

2. A device for switch-connecting as defined in claim 1 in which said switch means includes a double pole switch for each of said corresponding sets of said left and right positive and negative output circuits actionable simultaneously directing said main left and right speaker positive and negative input circuits into said corresponding sets of left and right positive and negative output circuits.

3. A device for switch-connecting as defined in claim I in which there are at least two different corresponding sets of left and right positive and negative output circuits.

4. A device for switch-connecting as defined in claim 1 in which there are at least two different corresponding sets of left and right positive and negative output circuits; and in which said switch means includes a double pole switch for each of said corresponding sets of left and right positive and negative output circuits actionable simultaneously directing said main left and right speaker positive and negative input circuits into that particular of said corresponding sets of left and right positive and negative output circuits.

5. A device for switch-connecting as defined in claim 1 in which said resistance of said first resistance means is a fraction of said resistance of said second resistor means.

6. A device for switch-connecting as defined in claim 1 in which said resistance of said first resistance means is in the general order of l to 4 ohms and said resistance of said second resistor means is in the general order of 50 ohms.

7. A device for switch-connecting as defined in claim 1 in which there are at least two diflerent corresponding sets of left and right positive and negative output circuits; in which said switch means includes a double pole switch for each of said corresponding sets of said left and right positive and negative output circuits actionable simultaneously directing said main left and right speaker positive and negative input circuits into that particular of said corresponding sets of left and right positive and negative output circuits; and in which said resistance of said first resistance means is a fraction of said resistance of said second resistor means. 

1. In a device for switch-connecting single and multiple pairs of left and right stereophonic speakers into a stereophonic unit amplifier circuit wherein the stereophonic unit may be either of a vacuum tube circuit type and a transistor circuit type; the combination of: main left speaker positive and negative input circuits and main right speaker positive and negative input circuits connectable to a stereophonic unit amplifier circuit; sets of left and right speaker positive and negative output circuits, each set of left speaker positive and negative output circuits having a corresponding set of right speaker positive and negative output circuits and each of said sets being connectable to a speaker; switch means selectively operable for selectively directing said main left speaker positive and negative input circuits into each set of left speaker positive and negative output circuits and for selectively directing said main right speaker positive and negative input circuits into each set of right speaker positive and negative output circuits; first resistor means connected in series in at least one of said main left speaker positive and negative input circuits and in at least one of said main right speaker positive and negative input circuits of a resistance for always providing a load for and preventing damage to transistors of a transistor circuit type of stereophonic unit in the event said unit is of the type and regardless of said operation of said switch means; and second resistor means connected in parallel across said main left speaker positive and negative input circuits and across said main right speaker positive and negative input circuits of a resistance for preventing overloading of vacuum tubes of a vacuum tube type of stereophonic unit in the event said unit is of said type and regardless of said operation of said switch means.
 2. A device for switch-connecting as defined in claim 1 in which said switch means includes a double pole switch for each of said corresponding sets of said left and right positive and negative output circuits actionable simultaneously directing said main left and right speaker positive and negative input circuits into said corresponding sets of left and right positive and negative output circuits.
 3. A device for switch-connecting as defined in claim 1 in which there are at least two different corresponding sets of left and right positive and negative output circuits.
 4. A device for switch-connecting as defined in claim 1 in which there are at least two different corresponding sets of lefT and right positive and negative output circuits; and in which said switch means includes a double pole switch for each of said corresponding sets of left and right positive and negative output circuits actionable simultaneously directing said main left and right speaker positive and negative input circuits into that particular of said corresponding sets of left and right positive and negative output circuits.
 5. A device for switch-connecting as defined in claim 1 in which said resistance of said first resistance means is a fraction of said resistance of said second resistor means.
 6. A device for switch-connecting as defined in claim 1 in which said resistance of said first resistance means is in the general order of 1 to 4 ohms and said resistance of said second resistor means is in the general order of 50 ohms.
 7. A device for switch-connecting as defined in claim 1 in which there are at least two different corresponding sets of left and right positive and negative output circuits; in which said switch means includes a double pole switch for each of said corresponding sets of said left and right positive and negative output circuits actionable simultaneously directing said main left and right speaker positive and negative input circuits into that particular of said corresponding sets of left and right positive and negative output circuits; and in which said resistance of said first resistance means is a fraction of said resistance of said second resistor means. 